VulnerabilityPublished 10 Nov 2026

CVE-2026-120212: Web-Simple (Perl module) · Cross-site Scripting

Affects Web-Simple (Perl module)Source CVE Database V5

Compare

Not known to be exploited : upgrade to 0.037 soon.

Data as of 10 Nov 2026, 17:51 UTC

Severity

High

Rated High by Threat Radar's AI analysis · CVSS not yet scored by NVD

Thin evidence

One scorer or none

Patch: Available – fixed in 0.037

Exploitation evidence

Disclosed: evidence found.
CVE published 10 Nov 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 10 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade Web-Simple (Perl module) to 0.037.

Affected software

Product	Affected	Fixed in
Web-Simple	Affected <0.037	Fixed in 0.037
CPANWeb-Simple`pkg:cpan/Web-Simple`Other threats	Affected <0.037	Fixed in 0.037

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Upgrade Web::Simple to version 0.037 or later, where the issue is fixed. No other mitigation is required as the vulnerability is addressed in the official fix.

Description

Web::Simple for Perl versions before 0.037 do not properly escape single quotes in HTML::Tags output, leading to a cross-site scripting (XSS) vulnerability. This occurs because single-quoted HTML attributes can be closed prematurely by an attacker-controlled value, allowing injection of malicious script. Double-quoted attributes are not affected. The issue is fixed in version 0.037.

Impact

An attacker who can control input interpolated into a single-quoted HTML attribute can inject arbitrary script code into the generated web page, potentially leading to XSS attacks. This can compromise user sessions, deface web content, or redirect users to malicious sites. Double-quoted attributes are not vulnerable to this issue.

Summary

Web::Simple versions prior to 0.037 for Perl fail to escape single quotes in HTML::Tags output. HTML::Tags and XML::Tags escape &, ", <, and > but not single quotes, which allows an attacker controlling a value interpolated into a single-quoted attribute to close the attribute and inject additional attributes such as event handlers. This results in a CWE-79 Cross-site Scripting vulnerability. The vulnerability is resolved in Web::Simple version 0.037.

CWE-79Improper Neutralization of Input During Web Page Generation (Cross-site Scripting) (opens in a new tab)
Base weaknessLikelihood of exploit: HighCWE Top 25 (2025): #1OWASP Top 10 A05:2025: Injection (opens in a new tab)
The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.
Architecture and Design · Libraries or Frameworks
Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
Implementation · Architecture and Design
Understand the context in which your data will be used and the encoding that will be expected. This is especially important when transmitting data between different components, or when generating outputs that can contain multiple encodings at the same time, such as web pages or multi-part mail messages.
Architecture and Design · Implementation · Attack Surface Reduction
Understand all the potential areas where untrusted inputs can enter your software: parameters or arguments, cookies, anything read from the network, environment variables, reverse DNS lookups, query results, request headers, URL components, e-mail, files, filenames, databases, and any external systems that provide…
OWASP Cheat Sheets
Cross Site Scripting Prevention (opens in a new tab)
DOM based XSS Prevention (opens in a new tab)
Injection Prevention (opens in a new tab)
Abuse Case (opens in a new tab)
Deserialization (opens in a new tab)
OWASP ASVS 4.0.3
V5.3.3 (opens in a new tab)
V1.5.1 (opens in a new tab)
Attack patterns
XSS Using MIME Type Mismatch (opens in a new tab)
DOM-Based XSS (opens in a new tab)
Reflected XSS (opens in a new tab)
Stored XSS (opens in a new tab)
Cross-Site Scripting (XSS) (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

Community reviews

Loading reviews…

Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 10 Nov 2026, 17:51 UTC

WeaknessesCWE-79

Technical details

References

Community reviews

Related threats